1. Field of the Invention
The present invention relates to a two way lighting control system with dual illumination sources. In particular, this invention relates to a lighting technology which can change the level of illumination via the performance of a passive infrared motion sensor and a photo cell control circuit.
2. Description of the Related Art
The two level lighting system of the present invention has a similar function as the prior art U.S. Pat. No. 5,747,937/Two Level Security Lighting System. However, the technology employed in the present invention is different from such prior art and is characterized with two significant merits; First, the present invention avoids the employment of a dimmer circuit (such as triac circuit) to achieve the function of two level illumination resulting into a lower manufacturing cost which helps to save consumers' initial spending. Second, because of no employment of dimmer circuit the present invention does not consume additional electric power for driving the dimmer performance. The energy efficiency of the present invention is therefore superior to such prior art. It helps consumers to save significant amount of energy expense over time. According to experiments the power efficiency of the present invention is as high as 95.7% while the power efficiency of such prior art is only 59% which means vast amount of power is used for the operation of dimmer circuit in the performance of such prior art.
The prior art uses the triac technology to generate two levels of illumination with a single illumination source light bulb; At dusk, the photo cell turns the power supply on and the control system manages the light bulb to illuminate at low level. When a living creature enters the detection area of the passive infrared motion detector, the control system immediately manages the light bulb to illuminate at high level and continues such high level illumination till the living creature leaves the detection area, then the system manages the light bulb to resume low level illumination in a short period of time. At dawn the photo cell turns off the power supply causing the low level illumination to cease during day time.
The present invention, being different from the above prior art which adopts a single bulb structure, uses two light sources structure to achieve similar function. One light source has a higher wattage load while the other light source has lower wattage load. The higher wattage light source is electrically connected to the passive infrared motion detector and then further connected to the photo cell. The lower wattage light source is directly connected to the same photo cell. At dusk, the photo cell turns on the power supply and the low level light source immediately turns on. The system therefore demonstrates a low level illumination. When a living creature enters the detection area of the passive infrared motion detector, the motion sensor instantly turns on the high wattage light source and the system then demonstrates dual illuminations simultaneously till the living creature leaves the detection area at which time the high wattage light source cease to illuminate in a short period of time. The system then resumes to low level illumination by the low wattage light source. At dawn the photo cell turns off the power supply causing the low wattage light source to cease illumination.